////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///  File:        AES_CPU_Impl_O0.cpp
///  Description: The CPU implementation for the AES using no optimizations at all
///               (based solely on the FIPS 197 Advanced Encryption Standard - AES).
///  Author:      Chiuta Adrian Marius
///  Created:     08-11-2009
///
///  Licensed under the Apache License, Version 2.0 (the "License");
///  you may not use this file except in compliance with the License.
///  You may obtain a copy of the License at
///  http://www.apache.org/licenses/LICENSE-2.0
///  Unless required by applicable law or agreed to in writing, software
///  distributed under the License is distributed on an "AS IS" BASIS,
///  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
///  See the License for the specific language governing permissions and
///  limitations under the License.
///
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#include "AES_CPU_Impl_O0.h"

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// The S box used to encrypt
__declspec(align(16)) const UINT8 sbox[256] =
{
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16  //F
};

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/// The reversed S box used to decrypt
__declspec(align(16)) const UINT8 rsbox[256] =
{
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, //0
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, //1
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, //2
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, //3
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, //4
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, //5
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, //6
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, //7
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, //8
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, //9
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, //A
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, //B
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, //C
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, //D
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, //E
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d  //F
};

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::SetKeyData(const UINT8 *keyData, UINT32 keyDataSize, AES_Key::AES_KeySize keySize)
{
    memcpy(m_key, keyData, keyDataSize);
    m_keySize = keySize;
    m_Nk = m_keySize >> 5;
    m_Nr = m_Nk + 6;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::EncryptBlock(UINT8 *dst, const UINT8 *src)
{
    UINT8 m_state[m_Nb][4];
    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            m_state[j][i] = src[i*4 + j];

    // Add the First round key to the state before starting the rounds.
    AddRoundKey(m_state, 0); 

    // There will be m_Nr rounds.
    // The first m_Nr-1 rounds are identical.
    // These m_Nr-1 rounds are executed in the loop below.
    for( UINT32 round = 1; round < m_Nr; round++ )
    {
        SubBytes(m_state);
        ShiftRows(m_state);
        MixColumns(m_state);
        AddRoundKey(m_state, round);
    }

    // The last round is given below.
    // The MixColumns function is not here in the last round.
    SubBytes(m_state);
    ShiftRows(m_state);
    AddRoundKey(m_state, m_Nr);

    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            dst[i*4 + j] = m_state[j][i];
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::DecryptBlock(UINT8 *dst, const UINT8 *src)
{
    UINT8 m_state[m_Nb][4];
    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            m_state[j][i] = src[i*4 + j];

    // Add the First round key to the state before starting the rounds.
    AddRoundKey(m_state, m_Nr); 

    // There will be m_Nr rounds.
    // The first m_Nr-1 rounds are identical.
    // These m_Nr-1 rounds are executed in the loop below.
    for( UINT32 round = m_Nr-1; round > 0; round-- )
    {
        InvShiftRows(m_state);
        InvSubBytes(m_state);
        AddRoundKey(m_state, round);
        InvMixColumns(m_state);
    }

    // The last round is given below.
    // The MixColumns function is not here in the last round.
    InvShiftRows(m_state);
    InvSubBytes(m_state);
    AddRoundKey(m_state, 0);

    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            dst[i*4 + j] = m_state[j][i];
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::AddRoundKey(UINT8 m_state[m_Nb][4], UINT32 round) 
{
    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            m_state[j][i] ^= m_key[round * m_Nb * 4 + i * m_Nb + j];
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::SubBytes(UINT8 m_state[m_Nb][4])
{
    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            m_state[i][j] = sbox[m_state[i][j]];
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::InvSubBytes(UINT8 m_state[m_Nb][4])
{
    for( UINT32 i = 0; i < 4; i++ )
        for( UINT32 j = 0; j < 4; j++ )
            m_state[i][j] = rsbox[m_state[i][j]];
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::ShiftRows(UINT8 m_state[m_Nb][4])
{
    UINT8 temp;

    // Rotate first row 1 columns to left
    temp = m_state[1][0];
    m_state[1][0] = m_state[1][1];
    m_state[1][1] = m_state[1][2];
    m_state[1][2] = m_state[1][3];
    m_state[1][3] = temp;

    // Rotate second row 2 columns to left
    temp = m_state[2][0];
    m_state[2][0] = m_state[2][2];
    m_state[2][2] = temp;
    temp = m_state[2][1];
    m_state[2][1] = m_state[2][3];
    m_state[2][3] = temp;

    // Rotate third row 3 columns to left
    temp = m_state[3][0];
    m_state[3][0] = m_state[3][3];
    m_state[3][3] = m_state[3][2];
    m_state[3][2] = m_state[3][1];
    m_state[3][1] = temp;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::InvShiftRows(UINT8 m_state[m_Nb][4])
{
    UINT8 temp;

    // Rotate first row 1 columns to right
    temp = m_state[1][3];
    m_state[1][3] = m_state[1][2];
    m_state[1][2] = m_state[1][1];
    m_state[1][1] = m_state[1][0];
    m_state[1][0] = temp;

    // Rotate second row 2 columns to right
    temp = m_state[2][0];
    m_state[2][0] = m_state[2][2];
    m_state[2][2] = temp;
    temp = m_state[2][1];
    m_state[2][1] = m_state[2][3];
    m_state[2][3] = temp;

    // Rotate third row 3 columns to right
    temp = m_state[3][0];
    m_state[3][0] = m_state[3][1];
    m_state[3][1] = m_state[3][2];
    m_state[3][2] = m_state[3][3];
    m_state[3][3] = temp;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::MixColumns(UINT8 m_state[m_Nb][4])
{
    for( UINT32 i = 0; i < 4; i++ )
    {
        UINT8 a, b, c, d;
        a = m_state[0][i];
        b = m_state[1][i];
        c = m_state[2][i];
        d = m_state[3][i];

        m_state[0][i] = Multiply(a, 0x02) ^ Multiply(b, 0x03) ^ Multiply(c, 0x01) ^ Multiply(d, 0x01);
        m_state[1][i] = Multiply(a, 0x01) ^ Multiply(b, 0x02) ^ Multiply(c, 0x03) ^ Multiply(d, 0x01);
        m_state[2][i] = Multiply(a, 0x01) ^ Multiply(b, 0x01) ^ Multiply(c, 0x02) ^ Multiply(d, 0x03);
        m_state[3][i] = Multiply(a, 0x03) ^ Multiply(b, 0x01) ^ Multiply(c, 0x01) ^ Multiply(d, 0x02);
    }
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void
AES_CPU_Impl_O0::InvMixColumns(UINT8 m_state[m_Nb][4])
{
    for( UINT32 i = 0; i < 4; i++ )
    {
        UINT8 a, b, c, d;
        a = m_state[0][i];
        b = m_state[1][i];
        c = m_state[2][i];
        d = m_state[3][i];

        m_state[0][i] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
        m_state[1][i] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
        m_state[2][i] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
        m_state[3][i] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
    }
}
